Yu–Wang system — classic 3D chaos (Yu & Wang) — dx/dt = a·(y − x), dy/dt = b·x − c·x·z + k·y, dz/dt = exp(x·y) − d·z. Classic chaotic a=15 b=30 c=3.2 d=2 k=−5.2 (c,d,k fixed). Dual a+b sliders. Exponential fold distinct from Liu (liu.html), Lü (lu.html), Chen–Ueta (chen.html), Chen–Lee, Rikitake, Moore–Spiegel, Rayleigh–Bénard, Hadley, Dequan–Li, Coullet, Burke–Shaw, Sprott–Linz A–S, Finance, Bouali, Genesio–Tesi, Arnéodo, Newton–Leipnik, Rucklidge, Wang–Sun, four-wing, Dadras, Halvorsen, Chua, Aizawa, Thomas, Rössler. Bulk centroid ≈ (0.02, 0.02, 6.46) from warm 20k + 80k RK4 @ dt=0.001. RK4, not liu.html, not lu.html, not chen.html. Gold low-alpha trail, cap 650. RM = settled silhouette, no animate-on.